<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>姓名案例计算属性实现</title>
    <script src="../js/vue.js"></script>
</head>

<body>
    <div id="root">
        姓：<input type="text" v-model:value=" firstName"><br><br>
        名：<input type="text" v-model:value="lastName"><br><br>
        全名：<span>{{fullName}}</span>
    </div>
</body>
<script>
    Vue.config.productionTip = false;
    new Vue({
        el: '#root',
        data: {
            firstName: '张',
            lastName: '三',

        },
        computed:{
            fullName:{
                //get有什么作用？当有人读取fullName时。get就会被调用，且返回值就作为fullName的值
                //get什么时候调用？1.初次读取fullName时、2.所依赖的数据发生变化时
                get(){
                    console.log('get被调用了')
                    return this.firstName + '--' + this.lastName;
                },
                //set什么时候被调用？当fullName被修改时
                set(){
                    // console.log('set',value);
                    const [ firstName, lastName ] = value.split('-');
                    this.firstName = firstName;
                    this.lastName = lastName; //依赖属性发生改变之后,计算属性自动改变
                }
            }
        }
    })
</script>

</html>